Its a common problem with the mechanical voltage regs inside the gas gauge that utilize a bi-metal strip that opens and closes a set of points as 12 volts gets applied. The result of them heating and cooling amounts to opening and closing the points rapidly which relatively maintains a 5 or 6 volt supply for fuel, temp, and oil pressure gauges. When they fail, they can do it one of two ways. Open or closed. If they fail open, the gauges mentioned will not read anything (best case scenario). If they fail closed, system voltage gets applied to the gauges and they all fry. The sytem can be upgraded by defeating the original in the fuel gauge and installing an RTE solid state IVR. Lots of info out there on the conversion.......Here's what it looks like completed. The little box in the upper left is from RTE. The extra red and black jumpers to the right are for a Voltmeter addition and unrelated to the IVR installation.
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